arduino pro mini 5v 16mhz serial speed not going beyond 230400

Development Tools IDE 1.x
1

Hi,
I am doing a arduino project where i need to use >500000 serial baud rate. With standard arduino uno board I could even reach to 1000000 baud rate, but when I use pro mini I am not able to reach beyond 230400 (115200 * 2). Going beyond spits out garbage in the serial console. Just to mention that I am using a pL2303 USB to UART as the pc communication device.
Can anyone explain what can be the problem.

Thanks,
Debojit

2

pL2303 USB to UART

Could that be your problem?

3

What is your chip?

4

Probably what's happening here is that you're specifying baud rates high enough that you can't get UART baud rate close enough (it's derived by dividing the system clock, so as you get close to the minimum, it's harder to get close to the baud rate you need - google Wormfood AVR baud rate - it's got a chart that calculates how close you can get to various baud rates based on the system clock.

However, when you are using a board with the 16u2 as the USB adapter, both the USB serial adapter AND the 328p are trying to get to the same baud rate, subject to the same limitation (system clock is 16mhz on the 16u2 as well). So the '328p's baud rate will be wrong on both boards - but with 16u2 as serial adapter, the serial adapter's baud rate will also be wrong in the same way.

5

ptnapivoski:
What is your chip?

http://www.prolific.com.tw/US/ShowProduct.aspx?pcid=41&showlevel=0017-0037-0041

Its a PL2303HX, probably a fake one, not sure though. One thing I want to mention that with the same module I could connect an ESP12 module with 921600 bps without any problem. So that is my concern, that it should behave in the same way for Arduino as well. Uno board can easily handle 1000000 bps. I don't know but let me clear my requirement. I want to connect arduino with esp via h/w serial for a high speed audio sample transmission. So I want to identify the source of the problem. Id it is the usb-uart module i have no problem but if it is the arduino then I dont know what to do. I can confirm that the ardiono pro mini is the 5v 16mz one.

Appreciate your help.

Thanks,
Debojit